This chapter outlines how modern accounting information systems (AIS) can support managerial decision-making in contemporary organizations. It also outlines some future trends regarding this topic. The chapter begins by describing the factors constituting different decision-making environments and data environments. This lays a foundation for describing what kind of information is needed in different contexts and how AIS can support managers in making informed decisions. Decision-making plays a major, many times crucial, role in managers' work as they aim to make their organizations prosper. The chapter discusses four basic decision-making situations for further analysis, including pricing, product mix, equipment replacement and outsourcing decisions. The decisions made and the experience gained in the decision-making process feed to learning and consequent development initiatives that influence, for example, perceptions regarding the role of AIS and, in the end, system development. Decision-making situations can be categorized either as operational or strategic.